Better Chat replaces the default chat in games by allowing you change and customize player name colors and prefixes. Plugins can add support for this plugin as well for compatibility, as running more than one chat plugin generally won't work otherwise.
/chat group add <group> -- Creates a new chat group
/chat group remove <group> -- Removes a chat group
/chat group set <group> <setting> <value> -- Changes a chat group setting
/chat group list -- Lists all chat groups
/chat user add <player|steamid> <group> -- Adds a player to a chat group
/chat user remove <player|steamid> <group> -- Removes a player from a chat group